What exactly lead to quantum physics

Okay...To understand this we should get back in 1650's when Sir Issac Newton introduced the corpuscular theory.His theory was all about light.
According to him,light was just made up of very small particle which he called corpuscles.The difference in size of these corpuscles lead to different colors.

His theory was later denied in 1629 by Huygens.He proposed a wave theory of light which said that light is a wave and so does it travels like a wave which he termed as wave fronts.Each wave-front led to generation of secondary wavelets.
Now was the time scientist were struggling to solve one of the most biggest mysteries about light being a wave or a Particle.Then came Albert Einstein who also contributed in this great discovery by bringing forward his theory of Photoelectric effect in 1905 and introduced Photons(I love this word).

Then came the man who was finally able to solve this question-Louis De Broglie,a french physicist who brought the idea of particle duality.
According to him light was made of particles which travel in a form of wave.

THIS LEAD TO QUANTUM PHYSICS!!!
Now we know that light is a particle that travels in a wave-like form.These particles are actually like a packet of energies termed "QUANTA" and many Quanta together form Quantum.This theory of Quantum physics has totally changed our way of seeing the world...